"This followed advice from Thames Valley Police about threats of a protest and his concern about the level of disruption this could cause to the people of Oxford plus the possible cost of policing."

Students from the two universities in the city, Oxford and Oxford Brookes, had planned a demonstration during the visit.

Representatives of the protest movement called the postponement "laughable", arguing the business secretary lacked the courage to face student concerns.

Mr Cable's withdrawal represents the most visible sign so far that the Liberal Democrats are suffering a surge of student anger over their acquiescence to the findings of the Browne Review, which raises the prospects of lifting the cap on fees.

Every Lib Dem MP signed a pledge before the election not to vote through any rise in tuition fees - a pledge that has come back to haunt the party in government.

Senior Lib Dems have attempted to salvage some support by claiming that a cap will remain, though will be raised to £7,000. Few analysts expect the move to calm student anger.

The party, which relies on a strong student constituency, has been enduring grim poll ratings since joining the coalition government.